TY - JOUR
T1 - Magnetic hysteretic phenomena in multiferroic HoMnO3 single crystals and polycrystals with nano- and micrometer particle size
AU - Galstyan, E.
AU - Lorenz, B.
AU - Martirosyan, K. S.
AU - Yen, F.
AU - Sun, Y. Y.
AU - Gospodinov, M. M.
AU - Chu, C. W.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/8/13
Y1 - 2008/8/13
N2 - We report on the magnetic properties of multiferroic hexagonal HoMnO 3 single crystals and polycrystalline samples with micrometer and nanometer particle size. We have studied the in-plane and out-of-plane magnetization of HoMnO3 single crystals under low applied magnetic fields in the temperature range below TNéel = 72 K and observe the bifurcation of zero-field-cooled and field-cooled curves at the Mn spin reorientation transition temperature at 34 K. In addition, the c-axis magnetization shows a ferrimagnetic-like behavior which may relate to the magnetic Ho3+ and Mn3+ domain boundary structures and sensitively respond to changes of the magnetic structure such as spin rotations at the phase transitions near 5 and 34 K. We also studied the particles' size dependent magnetic behavior in the HoMnO3 polycrystalline samples and observe the presence of a net magnetic moment at the surface due to the large surface/volume ratio. Below the Ho3+ ordering temperature of 5 K, magnetization curves as a function of applied magnetic field, in contrast to those for the single crystal, show hysteresis behavior with coercivity, which increases with diminishing particle size.
AB - We report on the magnetic properties of multiferroic hexagonal HoMnO 3 single crystals and polycrystalline samples with micrometer and nanometer particle size. We have studied the in-plane and out-of-plane magnetization of HoMnO3 single crystals under low applied magnetic fields in the temperature range below TNéel = 72 K and observe the bifurcation of zero-field-cooled and field-cooled curves at the Mn spin reorientation transition temperature at 34 K. In addition, the c-axis magnetization shows a ferrimagnetic-like behavior which may relate to the magnetic Ho3+ and Mn3+ domain boundary structures and sensitively respond to changes of the magnetic structure such as spin rotations at the phase transitions near 5 and 34 K. We also studied the particles' size dependent magnetic behavior in the HoMnO3 polycrystalline samples and observe the presence of a net magnetic moment at the surface due to the large surface/volume ratio. Below the Ho3+ ordering temperature of 5 K, magnetization curves as a function of applied magnetic field, in contrast to those for the single crystal, show hysteresis behavior with coercivity, which increases with diminishing particle size.
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U2 - 10.1088/0953-8984/20/32/325241
DO - 10.1088/0953-8984/20/32/325241
M3 - Article
AN - SCOPUS:49049117530
SN - 0953-8984
VL - 20
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 32
M1 - 325241
ER -